a WillPower has some strange quality to it. The Model P wasn't that far off. Don't know if DM has a Model P in 5 string. At any rate, even a Willpower in your 5 may not sound as much like the WillPower in your 4 as a different P would.

Nord these days seems to be the rising standard so probably a good probability shot. But if you don't want to spend the coin and aren't in any hurry, you can watch ebay for used 5 P's that come up then search the net for reviews on them. If they came out of a given bass, you can go to harmonycentral.com and read what owners have to say about the bass. If the bass gets good reveiws in the sound section and sound like something you'd want to check out, then give a go. When it comes right down to it, pup tone is trial and error.

Rerouting the bass is probably not a good idea - you'll be dealing with the same thing just with a different shaped pup.

I found split coils to sound rather P like to me. I assume that's because having 2 coils in series makes it that much closer to a P pup than a J. I'm also a firm believer in pup placement and think getting the location right is more important than the right kind of pup.